Fluid specimen cups are commonly used to collect and test fluid specimens for the presence or absence of specific “indicators” which show the presence of specific chemicals, hormones, antibodies or antigens and are commonly used for drug screening.
Collecting and testing fluid specimens carries a health risk for the person conducting the test and a contamination risk to the specimen or testing media. With a potential for contact with the sample by the operator or technician and its associated health and contamination risks, a sealed receptacle for preventing such contact is desirable. Testing devices as disclosed in Cipkowski U.S. Pat. No. 5,976,895 have required that a liquid specimen be placed in a specimen cup and that a technician manually insert and submerge a portion of a testing strip cartridge into the specimen through a narrow insertion slot. Liquid specimen can still spill through the slot, and a film of liquid specimen can remain on the cartridge if and when it is removed from the cup.
Various devices, such as that shown in Davis U.S. Pat. No. 5,119,830, show further reduction in the risk of contact by using chromatographic testing strips mounted in substantially sealed cup lid. The initiation of the testing procedure may be controlled by activating a frangible partition allowing passage of the fluid from the cup into a chamber in the lid containing the chromatographic test strip.
U.S. Pat. No. 5,403,551 Galloway requires inversion of the cup to an unspecified angle making adequate submersion of the test strips uncertain. Further, testing chambers that allow the flow of fluid onto the test strip upon inversion also allow the fluid to escape upon righting. Such action can inhibit the capillary action required in some test strips. Testing accuracy is often enhanced by proper orientation and immersion of the strips into the proper depth of the fluid. Many prior devices do not provide for such control of the fluid depth, volume and strip orientation. Some types of preliminary screening tests such as those directed toward detecting THC levels in urine often resulting from the use of marijuana require a minimum fluid depth to ensure an adequate level of accuracy. Thus there can often be a trade-off between retaining enough fluid for the confirmatory testing while devoting adequate fluid for preliminary screening.
Oftentimes, the results of a particular preliminary screening test will indicate that further more rigorous and accurate testing should occur. For example, if a preliminary screening test comes back positive for drug use, the conductors of the test may seek to conduct a more rigorous and accurate test to confirm the presence of the offending component. Such secondary testing is often referred to as confirmatory testing.
In many prior devices, the liquid specimen volume, as a whole, comes into contact with the test strip. That contact can change the chemical characteristics of the remaining specimen so that the confirmatory test cannot be performed on the fluid specimen as originally supplied by the donor. In other words, the portion of the specimen in contact with the strips is also capable of contacting and intermingling with the remainder of the specimen. Such intermingling can lead to contamination of the remaining sample to a degree which diminishes optimum further testing of that specimen.
In the past, this problem has been addressed by taking multiple liquid specimens potentially removed in time from when the original specimen was taken. One can easily appreciate that the taking of a subsequent specimen after a prolonged period allows for changes in the physiology of the test subject. For example, a person suspected of taking drugs can cease drug use whereupon tests taken days later may not turn up positive.
More recently, various specimen-collecting and testing cups such as those disclosed in Guirguis U.S. Pat. No. 6,277,646 and Ng et al., U.S. Pat. No. 6,726,879 have been proposed that provide for two amounts of the specimen to be separated from one another. In this way, the first amount can be subjected to the test strips without contaminating the second, separated amount.
Such devices suffer from being bulky, difficult to operate, expensive to manufacture and provide less than adequate amounts of fluid for conducting the preliminary or confirmatory tests. For example, the device of Guirguis provides for only a limited or relatively uncontrolled amount or aliquot of fluid for preliminary testing, thereby making it potentially difficult to adequately contact the multiple strips or preserve enough of the sample for confirmatory testing. Also, the introduction of the aliquot can increase pressure in the test chamber to a degree which can effect test accuracy.
Some devices such as one disclosed in Hudak et al., U.S. Pat. No. 7,300,633 require multiple steps, one step to initiate the preliminary screening test and another step to seal one or both of the separated specimen amounts. Such multi-step processes can be confusing to unskilled workers and lead to mistakes in processing.
Many preliminary tests require viewing of the results within a specific time frame after the test has been initiated. Therefore, it is important for the test to remain uninitiate-able by the donor. This also helps avoid tampering by the donor. However, it is often impractical for the test to be initiated by a doctor or other highly skilled person. Increasingly, tests are being performed and evaluated by relatively unskilled technicians. Therefore, the device needs to be relatively simple to operate to insure adequate exposure of the test strip and to provide accurate results. Devices that require precise actions by the test conductor such as the proper orientation of the strips during testing are a source for additional error.
To avoid the contamination or even the appearance of contamination it is desirable to delay separation of the fluid sample into the two portions for as long as possible, preferably right up until the screening test is initiated. One problem with some of the above devices is that it separates the two portions early on, potentially well before testing needs to occur. This gives time for the two portions to be treated differently though unintentionally. For example, one portion may be subjected to slightly different heating or lighting conditions. One portion might be subjected to a greater surface area of the cup leading greater potential for interaction with the surface materials. Further, different portions of the cup may contain different materials, for example one portion may have contacted a rubber O-ring material. Although such materials are selected to be chemically inert, it is possible for those materials to have undergone some manufacturing mistake to carry contaminants. Though the probability of contamination may be small, and the amount of contamination minute, it may still be significant in some instances. Therefore, a design which minimizes the potential for contamination or differences between the two portions would be preferred.
It is also advantageous to maximize the volume of fluid preserved for confirmatory testing. This is because some types of confirmatory tests can require more fluid or the test may need to be repeated. In addition, a larger volume is often less susceptible to contamination by its environment by the mere fact that contaminant concentration is lower.
Because of the need to avoid contamination or even the appearance of possible contamination, it is desired that the specimen test cups be disposable. Therefore, to maintain low cost, it is important that efficient manufacturing methods, low cost materials and low cost designs are provided.
There is, therefore, a need for a specimen collection and preliminary screening cup which exhibits one or more of the following characteristics: insures proper testing by allowing the test strips to be in continuous and controlled contact with and adequate amount and depth of the liquid sample, to properly orient test strips, provides simple testing procedures, is inexpensive to manufacture, is flexible in accommodating different types of testing procedures, and provides for a maximized portion of the specimen volume to be uncontaminated by the testing process.